1. Field of the Invention
The present invention relates to a pressure indicator for positive pressure protection masks that enables positive safe operation of the protection masks.
2. Description of Related Art
Respiratory devices, such as protection masks, also interchangeably referred to herein as gas masks or masks, are well known. Civilians, law enforcement, military personnel, fire fighters and other groups of individuals commonly referred to as “responders” (hereinafter referred to as “users”) wear masks for protection from an environment containing harmful and possibly fatal air-born toxins or any other such hazardous material. Such toxins and materials are hazardous to respiratory systems and generally take the form of harmful gases, vapors, and particulate matter. The respiratory hazards may also include various agents, such as nuclear, biological and chemical (NBC) agents, which may be in the form of particulates, vapors or aerosols.
One type of breathing apparatus, known as a Powered Air Purifying Respirator (PAPR) (also referred to herein interchangeably as “PAPR protection system”), is a fan-forced positive pressure breathing apparatus. PAPR protection systems are used in environments where the ambient air is relatively oxygen-rich and where filtering elements are effective in removing all contaminants from the ambient air before the ambient air enters the gas mask. PAPR protection systems typically include a gas mask, a filtering element to remove contaminants from ambient air, a blowing element, such as, a fan, and a power source to provide operational power to the blowing element. The fan or blowing element continously supplies filtered air to the gas mask. The filtered air replenishes the internal space of the mask, and the exhaled air, also known as spent air, is continually ejected.
Under certain circumstances, such as heavy workload or extreme body movement, for instance, protection masks can create openings (i.e., also known generally as “leaks”) by not completely and seamlessly fitting to the contours of the user's face, and thus, forming an imperfect seal. The openings allow unfiltered, ambient air directly into the internal space of the mask, which may pose serious and even fatal health risks to the user if the ambient air contains harmful toxins or other such hazardous material. PAPR protection systems help reduce health risks caused by masks prone to or having leaks by creating a pressurized environment in the internal space of the mask (also interchangeably referred to as an “overpressurized environment”). In particular, because of the positive pressure gradient between the internal space of the mask and the ambient environment, the internal air pressure caused by the powered circulation of filtered air prevents the unfiltered, ambient air from entering the mask.
Although PAPR protection systems have reduced the danger of allowing unfiltered, ambient air into the internal space of the mask, and in turn, have reduced the danger of inhaling and contacting unfiltered, ambient air by the user, PAPR protection systems do not completely eliminate health risks. In some cases, PAPR protection systems fail to operate properly, and the health risks increase accordingly. Typically, when the PAPR protection system fails to operate, the internal space of the mask depressurizes, i.e., the overpressurized environment is lost. There are numerous instances in which the PAPR protection system may fail to provide a safe environment for the user. For instance, a kinked air supply hose, an obstructed air-purifying filter, a depleted blower battery, or an excessive demand for filtered air by the user may compromise the powered airflow caused by the PAPR protection systems, reducing the air pressure in the internal space of the mask. In each of these examples, the compromised PAPR protection system reduces positive pressure in the internal space of the mask, and thus, allows ambient air to enter the internal space, in the event that openings (i.e., leaks between the user's facial contours and the mask) were present.
The effectiveness of the PAPR protection system, which is typically measured in the level of safety provided to users, is directly correlated with the ability of the PAPR protection system to provide filtered air to the user while preventing unfiltered, ambient air from entering the internal space of the mask. Thus, in the event the safety of PAPR protection system is compromised, i.e., unfiltered, ambient air enters the internal space of the mask, users have a limited amount of time to exit or escape the environment having unfiltered, ambient air containing toxins and other such hazardous material (generally known as the “hot zone”). The present technology only includes devices that sense the volume of air in the mask, as opposed to the air pressure in the mask. Unfortunately, such technology provides an unreliable and indirect measure of whether the protection mask is safe. Presently, there is no reliable mechanism for the user to determine whether the PAPR protection system is functioning properly, and in turn, there is no mechanism for the user to determine whether the PAPR protection system is safe. Specifically, there is no mechanism for the user to determine whether the PAPR protection system has a positive air pressure within the internal space of the mask.
There is a need for a PAPR mask that provides users of the mask with information and feedback regarding the level of filtered air flow to the internal space of the mask. In particular, there is a need for a pressure indicator system, which measures the air pressure in the internal space of the mask and alerts users as to whether there is positive pressure in the mask and the actual value of the pressure gradient. Moreover, there is a further need for a pressure indicator system associated with the PAPR mask that informs the user whether the air entering the internal space of the mask is safe, i.e., whether filtered air rather than ambient air is filling the internal space of the mask.